A prosecution witness who specializes in human decomposition testified in the David Westerfield trial yesterday that many factors must be considered when estimating Danielle van Dam's time of death, not just the presence of insects.

Prosecutors called the forensic anthropologist to counter insect evidence presented by the defense that indicated the girl's body wasn't dumped until after police named Westerfield as a suspect and placed him under constant surveillance.

Testimony from William Rodriguez, a private consultant, provided several scenarios to explain why, as the defense has argued, insects didn't reach the girl's body until two weeks after her parents reported her missing.

When the 7-year-old's remains were found off Dehesa Road, east of El Cajon, on Feb. 27, her skin had mummified. Rodriguez said it had become "shrunken, shriveled, hard" and took on a "leathery appearance," which might have put off flies looking for a place to lay their eggs. The body produces a "hard case" as the soft tissue dries up, he said.

Ants and other scavengers like dogs, coyotes and wolves could have carried off and eaten the flies' eggs, he said. Also, low nighttime temperatures, which caused frost in the Dehesa Road area in early and mid-February, could have also prevented flies from laying eggs on her body, he added.

"It's like landing on a little iceberg," Rodriguez said.

But under cross-examination by defense attorney Steven Feldman, Rodriguez conceded he isn't an insect expert and that he didn't examine the specimens collected at Danielle's autopsy.

He was the last witness in the seventh week of testimony in the capital murder trial, in which Westerfield faces charges of kidnapping and killing the girl, who lived two doors from Westerfield in Sabre Springs.

Rodriguez testified during the rebuttal stage of the trial, when the prosecution calls witnesses to contradict testimony from defense witnesses.

He said he reviewed a variety of evidence in the trial before he reached his conclusion, including 182 autopsy photographs, 234 photos from the site where Danielle's body was discovered and an array of weather data for the area.

Rodriguez testified that he also examined reports and testimony of two forensic entomologists and the county medical examiner. He also visited the site Tuesday with prosecutor Jeff Dusek and several investigators, collecting road temperatures and observing the foliage.

Taking into account all that information, Rodriguez determined that the victim could have been dead four to six weeks when her body was discovered Feb. 27.

But he said it's not an "exact science." He said there's no way to determine precisely when someone died, although he has spent his career searching for a methodology.

"To this day, we do not have anything," Rodriguez said.

The defense raised questions about his theory because Danielle's body was found 25 days after she was reported missing.

But Rodriguez said the four-to-six-week timetable was his best estimate based on the advanced stage of mummification of the girl's body.

Each scientific expert who has testified has provided a different estimate for the time of death or the time insects had access to the body.

Neal Haskell, a forensic entomologist from Indiana who testified for the defense, said insects had access Feb. 14-21, but that it could have been as early as Feb. 12. San Diego entomologist David Faulkner said the girl's body was exposed to the elements between Feb. 16 and 18, but he allowed for the body being outdoors longer.

Dr. Brian Blackbourne, the county medical examiner, testified that the girl could have been dead from 10 days to six weeks when her body was discovered.

The trial will not be in session today. On Monday, the attorneys and judge will discuss jury instructions. Testimony will resume Tuesday.

Key testimony

William Rodriguez, a forensic anthropologist, testified as a prosecution witness to counter insect evidence that the defense says proves Danielle van Dam's body wasn't dumped until after David Westerfield was under 24-hour police surveillance.

Witnesses

James Watkins, a San Diego police computer expert, finished his testimony about pornographic computer images found in Westerfield's house.

William Rodriguez, the anthropologist, testified that Danielle was so small that her body could have mummified as soon as 24 hours after her death, depending on a variety of factors. Prosecutors argue that the condition of her body delayed blowflies from entering it, which might explain some of the insect evidence presented by Westerfield's attorneys.

But Rodriguez said he came to his own conclusions after reviewing transcripts, reports and evidence. He said he used the other experts' findings in forming his opinion.

"Any good scientist would," he said.

He testified that Danielle's body mummified rapidly – as quickly as 24 hours after she was killed.

Rodriguez said low humidity speeds up mummification, as do especially warm or cold temperatures. The process also tends to happen more quickly in children's small bodies, he added.

Flies aren't attracted to mummified bodies because adult flies can't chew and need soft places to feed, he said. When the eggs hatch into larvae, they also need something soft to eat, he said.

"The tissues can be so hard that the larvae can't penetrate them," Rodriguez said.

If there's no food source, he said, adult flies find somewhere else for their young. He said fly eggs that have already been laid will shrivel up and die.

Rodriguez said the body passes through a specific sequence of stages after death. He described the first stage as "fresh" soon after the person dies. Gases then build up in the abdomen and chest, and the body expands and bloats.

He said the skin becomes slippery and breaks down, and the body begins to undergo a massive breakdown. The organs become liquefied, and liquids pass out of the orifices. The body deflates, and gradually the soft tissues are either eaten or disintegrate until only the skeleton remains.